LegaSea spokesman Richard Baker told the Herald tonight no one had yet come forward taking responsibility; but the group felt the high number of quality fish pointed more towards a commercial vessel, rather than recreational fishermen.
"It's sickening. How it happened fades into insignificance. The reality is that dead fish are dead fish. We're trying to rebuild a fishery and this is still going on.
"You'd have to be pretty certain that it wasn't a recreational fisher. I've never been that lucky to catch that many fish,'' Mr Baker said.
"They might not have been dumped. But one of the other big concerns - that's 6km of fish on the beach that we actually get to see. But what haven't we seen? What hasn't washed ashore? And that's the sad part of it."
Mr Baker said if the dumping of the fish was intentional, more needed to be done to ensure this could not happen again - with the instalment of cameras on commercial trawling vessels, for example.
"We're busy trying to rebuild a fishery. There's that saying that 90 per cent of the fish is caught by 10 per cent of the fishermen and that's so true - our fishery is still relatively depleted and we'd love to see it rebuilt so people can reasonably go out there are catch a feed of fish.
"This is just rubs it into the public's face and it's happening far too frequently.''
The LegaSea group has informed the Ministry of Primary Industries, who sent representatives to assess the situation today.